Send server.root to integrate with GitHub

[chuchuva]

Per https://rollbar.com/docs/github/ and https://rollbar.com/docs/just-your-code/

Rollbar is better with GitHub! [...] link your Rollbar stack traces to the code where it happened, resolve items when a particular commit is deployed, and show the commits that were included with each deploy.

In order to let our servers know that you want it to try linking your stack trace to the files on GitHub you should send the "server.root" key. A lot of the time that can be "/", to indicate that all files can be linked to a file in GitHub.

All official Rollbar notifiers can send this key. See the documentation for your notifiers to learn exactly how.

[AlbertoMonteiro]

Nice one, a PR would be welcome!!

[simonbuchan]

It is already sending a server.root in ServerModelBuilder, the problem is that it's actually sending the server root :) It looks like Rollbar expects that your code is dynamic, so source paths in stack frames are the path on the server, not the build machine like they are in .NET (and presumably Java, etc...).

To fix this it would be easiest to just ask the user to provide it in the configuration, so they can use [CallerFilePath] or whatever floats their boat.